The Mass holds a "special" place in Catholicism. Mass is not just a place where Catholics gather to worship - far from it! It is not like a Protestant church service (no matter what denomination). During the holy Mass, we unite ourselves with the Church, we offer our entire selves to God wholly and without reserve, but most importantly we unite ourselves with Christ through the Holy Eucharist. Mass is the most sacred thing that we have on this earth.
The Mass is not about this.
Halloween costumes?.... Did I hear drums? Tambourines?..... A minister of the Holy Eucharist dressed up as a devil?.... While I'm sure that these people have the best intentions, THIS IS WRONG. The Mass should be treated with reverence, as the holy place that it is; it's not a joke, or a social gathering.
For those of you who aren't Catholics and have never attended Mass... that sort of thing does not represent us, and it is not what we are about.